As Secretary of State for Northern Ireland, James Brokenshire was at the heart of negotiations that will shape the UK's future.

Then, two weeks ago, he was told he has a lesion on his lung and resigned from the Cabinet to focus on his health. This week he will have surgery for a condition that has put politics into perspective.

Here, James Brokenshire talks about his difficult few weeks:

Several weeks ago I had an odd niggle with my lungs that was out of the ordinary that I wasn't happy with.

I think you know intuitively if you have something wrong and I knew that I needed to follow things through.

I went to see my GP, who was very thorough and organised an X-ray, and then referred me to a consultant.

They arranged a series of diagnostic tests that I was taking while continuing day-to-day work in Government.

There was one acute moment, when we were literally in the final stages of negotiations of the first phase of the Brexit deal, and I was working late into the night in Downing Street.

The Prime Minister went off to Brussels to conclude the agreement but I knew that I was going to hospital to have a bronchoscopy the following morning.

It is quite an invasive procedure where they put a probe down your throat to see what is happening, and ultimately that is how they found out.

In the New Year I was told I have a small lesion on my right lung that would require surgery to remove it, along with a surrounding portion of the lung.

When you get health news like this it's a real jolt.

Image:James Brokenshire says he will now focus on his family and his health

I have never smoked in my entire life so the thought that I might have something like this never entered my mind.

The other strange part is that physically I feel perfectly well.

This weekend I went out for a 10-mile walk knowing that I've got a serious problem that needs to be dealt with.

It is quite a lot to get your head around.

When I was told I was very clear that I could not deal with this while remaining a member of the Government.

I couldn't see how I could continue to give the effort and the energy required for front-line politics, particularly given the current challenges in Northern Ireland.

For me it was obvious what needed to happen.

I resigned on my 50th birthday, which was not how I imagined the day would go, but I needed to focus on my health and my family.

Colleagues from all parties, both at Westminster and Stormont, have been incredibly supportive and positive.

In politics you argue your point with all of your effort, energy and endeavour, but when it comes to things like this you receive genuine warmth from across the board.

I've also had support on social media from friends, local constituents and people I've never met, some of whom have started their messages by saying, "I'm not a Conservative, I've never voted Tory, but I wish you well." That is very humbling.

While it has been tough, the kindness and support I have received from medical staff has been outstanding, and renews and underlines what I've always felt about the NHS.

Making the decision to step back from front-line politics having got into a position of serving in Government is hard.

It has been a tough couple of weeks going through the implications.

But my family, my wife Cathy and the children, have given me strength and encouragement to deal with the physical battles that lie ahead.